您好我有一个delphi问题，一直在吃我，我需要帮助 [英] Hello I have a delphi question that has been eating at me and I need help

问题描述

这是一个delphi项目，我需要帮助，如编程项目的历史好吧所以它是这样的，我的代码在搜索系统上充实，基本上如果你搜索一个空白的Tedit它会给你一个错误，现在我遇到了一个障碍，因为如果搜索到的项目不存在，我希望它产生一个新的错误......这就是我吃的代码。

"This is a delphi project that I need help with as in History of programming project" ok so it goes like this, I have my code fleshed out on the search system where basically if you search a blank Tedit it will give you an error, now I have hit a road block as I want it to produce a new error if the item searched doesnt exist... this is the code that is eating at me.

procedure TForm1.BtnSearchClick(Sender: TObject);
var
sStudent :String;
begin
    sStudent:=CbSearch.Text;
 if sStudent = ''
then
begin
    Application.MessageBox('No data has been inputed. Please Input a name to search', 'Error no information to search', 0);
end
else
begin
    RDisp.Lines.LoadFromFile('Students\' + sStudent + '.zip');
end;
end;

我知道在Rdisp.Lines下面我需要提供另一个条件声明，但我不知道如何去做...请帮助



我尝试过：



我尝试添加一个if语句，但是一旦它崩溃我的程序就摆脱了它...我知道我需要一个if sStudent =''等，但我没有一个线索是什么...

I know that below the "Rdisp.Lines" I need to provide another conditional if statement but I dont know how to go about it... Please help

What I have tried:

I have tried adding an if statement but I got rid of that as soon as it crashed my program... I know I need an "if sStudent='' "etc, but I dont have a clue what to do it on...

推荐答案

听起来你正在寻找 FileExists 功能 [ ^ ]：

It sounds like you're looking for the FileExists function[^]:

if sStudent = ''
then
begin
    Application.MessageBox('No data has been inputed. Please Input a name to search', 'Error no information to search', 0);
end
else if Not FileExists('Students\' + sStudent + '.zip')
then
begin
    Application.MessageBox('Student file not found.', 'Error file not found', 0);
end
else
begin
    RDisp.Lines.LoadFromFile('Students\' + sStudent + '.zip');
end;

然而，目前尚不清楚 LoadFromFile 方法 [ ^ ]支持读取Zip文件。我希望它只支持文本文件。

However, it's not clear whether the LoadFromFile method[^] supports reading Zip files. I would expect it to only support text files.

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